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From: Kishon Vijay Abraham I <kishon@ti.com>
To: Tony Lindgren <tony@atomide.com>
Cc: "Jonathan Corbet" <corbet@lwn.net>,
	"Benoît Cousson" <bcousson@baylibre.com>,
	"Rob Herring" <robh+dt@kernel.org>,
	"Mark Rutland" <mark.rutland@arm.com>,
	linux-mmc@vger.kernel.org, devicetree@vger.kernel.org,
	linux-kernel@vger.kernel.org, linux-omap@vger.kernel.org,
	kishon@ti.com
Subject: [PATCH v4 03/14] ARM: dts: dra7-mmc-iodelay: Add a new pinctrl group for clk line without pullup
Date: Fri, 27 Apr 2018 17:38:54 +0530	[thread overview]
Message-ID: <20180427120905.3665-4-kishon@ti.com> (raw)
In-Reply-To: <20180427120905.3665-1-kishon@ti.com>

During a short period when the bus voltage is switched from 3.3v to 1.8v,
(to enumerate UHS mode), the mmc module is disabled and the mmc IO lines
are kept in a state according to the programmed pad mux pull type.

According to 4.2.4.2 Timing to Switch Signal Voltage in "SD Specifications
Part 1 Physical Layer Specification Version 5.00 February 22, 2016", the
host should hold CLK low for at least 5ms.

In order to keep the card line low during voltage switch, the pad mux of
mmc1_clk line should be configured to pull down.

Add a new pinctrl group for clock line without pullup to be used in boards
where mmc1_clk line is not connected to an external pullup.

Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>
---
 arch/arm/boot/dts/dra7-mmc-iodelay.dtsi | 19 +++++++++++++++++++
 1 file changed, 19 insertions(+)
 create mode 100644 arch/arm/boot/dts/dra7-mmc-iodelay.dtsi

diff --git a/arch/arm/boot/dts/dra7-mmc-iodelay.dtsi b/arch/arm/boot/dts/dra7-mmc-iodelay.dtsi
new file mode 100644
index 000000000000..aa0947266526
--- /dev/null
+++ b/arch/arm/boot/dts/dra7-mmc-iodelay.dtsi
@@ -0,0 +1,19 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * MMC IOdelay values for TI's DRA7xx SoCs.
+ * Copyright (C) 2018 Texas Instruments
+ * Author: Kishon Vijay Abraham I <kishon@ti.com>
+ */
+
+&dra7_pmx_core {
+	mmc1_pins_default_no_clk_pu: mmc1_pins_default_no_clk_pu {
+		pinctrl-single,pins = <
+			DRA7XX_CORE_IOPAD(0x3754, PIN_INPUT_PULLDOWN | MUX_MODE0) /* mmc1_clk.clk */
+			DRA7XX_CORE_IOPAD(0x3758, PIN_INPUT_PULLUP | MUX_MODE0) /* mmc1_cmd.cmd */
+			DRA7XX_CORE_IOPAD(0x375c, PIN_INPUT_PULLUP | MUX_MODE0) /* mmc1_dat0.dat0 */
+			DRA7XX_CORE_IOPAD(0x3760, PIN_INPUT_PULLUP | MUX_MODE0) /* mmc1_dat1.dat1 */
+			DRA7XX_CORE_IOPAD(0x3764, PIN_INPUT_PULLUP | MUX_MODE0) /* mmc1_dat2.dat2 */
+			DRA7XX_CORE_IOPAD(0x3768, PIN_INPUT_PULLUP | MUX_MODE0) /* mmc1_dat3.dat3 */
+		>;
+	};
+};
-- 
2.17.0

  parent reply	other threads:[~2018-04-27 12:13 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-04-27 12:08 [PATCH v4 00/14] dra7: mmc: Update mmc dt node to use sdhci-omap Kishon Vijay Abraham I
2018-04-27 12:08 ` [PATCH v4 01/14] ARM: dts: dra72-evm-common: Remove mmc specific pinmux Kishon Vijay Abraham I
2018-04-27 12:08 ` [PATCH v4 02/14] ARM: dts: dra71-evm: Add "vqmmc-supply" property for mmc2 Kishon Vijay Abraham I
2018-04-27 12:08 ` Kishon Vijay Abraham I [this message]
2018-04-27 12:08 ` [PATCH v4 04/14] ARM: dts: am57xx-idk: Use pinctrl group from dra7-mmc-iodelay.dtsi to select pulldown Kishon Vijay Abraham I
2018-04-27 12:08 ` [PATCH v4 05/14] ARM: dts: dra71-evm: " Kishon Vijay Abraham I
2018-04-27 12:08 ` [PATCH v4 06/14] ARM: dts: am574x-idk: Add pinmux configuration for MMC Kishon Vijay Abraham I
2018-04-27 12:08 ` [PATCH v4 07/14] ARM: dts: am57xx-beagle-x15/am57xx-idk: Fix pinctrl-names Kishon Vijay Abraham I
2018-04-27 12:08 ` [PATCH v4 08/14] ARM: dts: dra72-evm-common: Add wilink8 wlan support Kishon Vijay Abraham I
2018-04-27 12:09 ` [PATCH v4 09/14] ARM: dts: dra7-evm: Model EVM_3V6 regulator Kishon Vijay Abraham I
2018-04-27 12:09 ` [PATCH v4 10/14] ARM: dts: dra7-evm: Add wilink8 wlan support Kishon Vijay Abraham I
2018-04-27 12:09 ` [PATCH v4 11/14] ARM: dts: dra76-evm: " Kishon Vijay Abraham I
2018-04-27 12:09 ` [PATCH v4 12/14] ARM: dts: dra7: Use sdhci-omap programming model Kishon Vijay Abraham I
2018-04-27 12:09 ` [PATCH v4 13/14] ARM: dts: dra7: Add high speed modes capability to MMC1/MMC2 dt node Kishon Vijay Abraham I
2018-04-27 12:09 ` [PATCH v4 14/14] Documentation: ARM: Add new MMC requirements for DRA7/K2G Kishon Vijay Abraham I
2018-05-03 17:40 ` [PATCH v4 00/14] dra7: mmc: Update mmc dt node to use sdhci-omap Tony Lindgren

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